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According to Golder (1995) samples for metals, chloride, sulfate, and sulfide were collected from monitoring wells MW-1 through MW-3 were collected on December 12, 1992, piezometers PS-4 through PS-7 and PS-9 on January 29, 1994. Piezometers PS-1, PS-2, PS-3 and PS-10 on March 9, 1994. Samples for fluoride, ammonia, nitrate, nitrite, sulfate, sulfide, and total phosphorus were collected from piezometers PS-1 through PS-10 on May 6, 1994. Samples for all analyses were collected from PS-11 on May 7, 1994 and from PS-12 through PS-17 on May 18, 1994.

No levels of selenium or sulfide was detected in the above groundwater samples and have not been included.

µg/dL = micrograms per deciliter (a) Results less than the detection limit of 2.0 µg/dl were designated 1.0 µg/dl for mean calculations. (b) Blood lead level concentrations from a national survey (Brody, 1994).

The Illinois Department of Public Health (IDPH) responses to the "Summary of Comments" in the comment package received in October 1998 as follows, numbered according to the original statements.

The statement in the public health assessment (PHA) that "the site is a public health hazard" is the appropriate conclusion category. IDPH selected that category using ATSDR criteria and guidance.

IDPH screened volunteers in DePue in 1993 because the Illinois Environmental ProtectionAgency (IEPA) asked for our department's opinion regarding an immediate clean up. Theresults of the biological screening indicated that this site should not be considered an "urgentpublic health hazard," and IDPH did not recommend an immediate clean up. IDPH did notconduct a "medical evaluation" of the community, nor did we conduct a case-controlled"study." IDPH was able to screen volunteers for two metals (lead and cadmium) quickly andwith very limited funds. Only venous blood samples and random urine samples werecollected and analyzed. Blood samples reflect only recent lead and cadmium exposure. Although cadmium in urine can reflect accumulated body burden, levels respond to recent exposure. Levels rise sharply when the critical level for renal damage is reached.

The PHA is not a quantitative risk assessment as developed by USEPA, nor is the PHAprocess considered "risk assessment modeling." The objective of the PHA is to evaluatecurrent, past, and possible future exposures and to provide information on health implicationsof those exposures.

IDPH agrees that the efforts made by the DePue Group with IEPA oversight has served toimprove exposure conditions. Additional statements about improved conditions have beenadded to the PHA. When IDPH is informed of successful mitigating activities and is givendata packages, we are able to consider the impact activities have on reducing exposures andcan issue statements reflecting that impact.

Please refer to answer #1. IDPH again emphasizes that the cadmium screening, as with bloodlead screening, was done to answer the question as to whether immediate action was needed tostop exposure. The screening was not population comprehensive and cannot be used toindicate levels of past exposure or the potential for future exposure.

Again, IDPH agrees that the selected exposure conditions are conservative. When evaluatingconditions that can impact human health, especially the health and well being of children,IDPH and ATSDR feel that the evaluation must be conservative. IDPH also agrees thatcurrent conditions, clean up efforts, and the considered worker protection activities serve toreduce exposures. Clean up efforts may also reduce off-site metal concentrations, andtherefore, future exposures should be less problematic.

The phrase "of concern" has been changed to "of interest" for all metals. Exposure frequencyvalues have been revised for children and adults.

The arsenic evaluation was based on screening values developed by ATSDR. The ATSDR airguideline at that time was lower than some of the concentrations found in the ambient airsamples (0.0002 microgram/cubic meter). IDPH agrees that the arsenic screening values arevery low concentrations, sometimes lower than background levels. The discussion of arsenicin air has been removed from the current document because any exposure that occurred at thelevels and duration of time found would not be expected to result in adverse health effects.

The discussion of cadmium has been revised to reflect the current conditions at the site.

No screening values are available for lead concentrations in soil. Limited information is available to determine how much lead in different environmental media contribute to increased blood lead levels. The sentence has been modified to clarify the issue.

IDPH feels that we have stated that many sources of metals exposure exists in ourenvironment and that some metals are nutrients at community meetings, health professionaleducation activities, and within the PHA drafts during the years that IDPH has been involvedat this site. We feel that we have been careful during educational activities to present theseissues regarding common metal exposures and will continue to do so.

IDPH is aware of the safety factors included in the development of health comparison values;however, EPA's RfDs and ATSDR's minimal risk levels might not protect hypersensitive(allergic) individuals.

IDPH appreciates the information provided by the DePue Group regarding the site's past andcurrent operations and have revised statements which were unintentionally confusing ormisleading. The specific comments included in Appendix A have, for the most part, beenconsidered in revising the statement, phrase, or word in question. IDPH thanks all themembers of the DePue Group for their careful and thorough perusal.

We have included a glossary developed by ATSDR to assist readers. Thank you for this suggestion.

Dr. Schiffer's report has been more fully discussed within the body of the PHA.

We appreciate the DePue Group's investigation of the pH data, and those discussions havebeen removed from the PHA. IDPH must depend upon EPA to complete the QA/QCactivities associated with the USEPA risk assessment guidance on data usability and often arenot provided with the laboratories' documentation. That is the rationale behind including the qualifying statement in the PHA.

Appendix A. The specific comments were considered while finalizing the PHA and were helpful in developing a clearer, more concise document. Our response to your specific comments are included as an attachment.

As you know, the DePue site has been very dynamic in recent years. Therefore, we have experiencedsome difficultly keeping current and continuously updating any document that attempts to maintain ageneral summary of activities. This PHA is somewhat preliminary because a comprehensive site-wide remedial investigation has yet to be completed. Because the site was listed on the NationalPriorities List, ATSDR is required to release the PHA within one year of listing or proposed listing,although important sampling efforts are currently underway. IDPH expects additional site reviewsand updates will be necessary as environmental assessments and remediation activities continue, datapackages become available, and reports are finalized. At this time, many earlier concerns listed inearlier drafts of the PHA have been addressed DePue Group actions as well as by IDPH and other agencies.

Responses to Comments in Appendix A

Page

Para

Line

Response

1-2

First two pages are a summary which has been revised to include the DePue Group's general suggestions, while some of the more specific details suggested here are considered in later sections of the PHA.

1

1

1

Sentences revised.

1

1

3

Sentence revised.

1

2

6

Sentence modified and moved to end of summary section.

1

3

3

Sentence modified.

1

3

6

Summary modified.

2

2

2

Sentence modified and moved.

2

2

6

Sentence revised

2

3

2

Document discussions were expanded to include two conclusions: that no urgent public health hazard was demonstrated by the health outcome data (biological screening), and that the site is considered a public health hazard because exposures have occurred in the past and the opportunity for potential exposures remain for some metals.

3

2

2

Sentence revised.

3

2

4

Sentence modified.

3

2

4

Sentence revised.

3

2

13

Sentence added.

3

3

1

Sentence modified.

3

5

9

Sentence revised.

4

1

1

Sentences modified.

4

1

6

Sentence modified.

4

1

10

Sentence modified.

4

1

16

Sentence added.

4

2

2

Comments on improved fencing added in description of each area.

4

2

3

Sentence revised.

4

2

5

Sentence revised.

4

3

5

Sentence revised.

4

4

1

First sentence deleted. Statement from Gibb moved to paragraph describing main smelting operations area.

Statement included regarding process of soil erosion and sedimentation.

6

3

4

Sentence revised.

7

2

Paragraph removed.

7

Bullets incorporated into discussions of the management of each area: smelting operations; inorganic compound manufacturing; gypstack; south ditch; Lake DePue. Operation years provided in comments incorporated into discussions.

IEPA could not find any information on private well sampling. Sentence modified.

11

2

4

Sentences modified.

11

3

5

Sentence revised.

12

3

3

Sentence revised.

12

4

item 3

Labeling of the comparison values double checked. Table on air data removed since IEPA approved discontinuing sampling because values were not high concentrations. The most conservative comparison value is used; sometimes that value has a cancer endpoint, and sometimes other health endpoints are considered.

14

2

1

Sentence revised.

14

2

2

Sentence revised.

14

2

9

Sentence revised.

14

4

5

Sentence revised.

15

1

2

Sentence modified.

15

2

1

Sentence revised.

15

2

2

Sentence modified.

16

4

1

Sentence revised.

16

5

2

Data associated with pH values deleted.

17

1

2

Sentence modified.

17

1

3

Sentence added.

17

5

1

Sentence revised.

17,18

7

Bullets removed and statements developed into text.

19

1

3

Sentence revised.

19

4

1

Section revised.

20

2

3

Paragraph deleted.

20

2

4

Sentence revised.

20

3

4

Sentence revised.

20

3

1

Sentence modified.

20

5

1

Sentence modified.

21

1

3

Paragraph modified.

21

1

5

Paragraph modified.

21

4

QA/QC statement qualifies assumptions that data were validated as required by EPA.

Statement added regarding the extrapolation between animal experimentation and the development of protective human comparison values.

25

3

5

Sentence modified.

25

5

7

The data that were evaluated are included in the tables. Including discussions of each eliminated metal adds considerable length to the document. Statement referring to these data included.

25

6

Paragraph revised so that exposure parameters are consistent with Table 19. Table 19 revised as well. IDPH concurs that frozen soil during cold months of the year should not be included in the exposure calculations.

26

3

1

Paragraph modified.

26

3

1

The ATSDR comparison values for arsenic are conservative. Arsenic is a human carcinogen, and the CREG for air, based on the concept of one-in-a-million excess cancer rate, is 0.0002 micrograms per cubic meter. Comparison values are used only to select contaminants for further evaluation. In reviewing the air data, the large majority of quarterly samples were below detection limits, so exposure was minimal. Table on air data removed from PHA. Also, because arsenic concentrations in soil are not expected to exceed comparison values and because a second source may be in the vicinity (coal-fired power plant), arsenic has been eliminated as a contaminant of interest.

26

4

Exposure calculations adjusted for a typical (non-pica) child, keeping body weight consistently 16 kilograms and adjusting exposure frequency to 3/4 of the year (39 weeks). Because these calculated potential doses remain above current MRLs for ingestion of cadmium, cadmium remains a contaminant of interest.

26-28

Paragraphs revised.

27

1

Statement revised.

27

1

1

More discussion included regarding common lead sources.

27

2

6

Statement revised.

27

4

3

Paragraph expanded to clarify.

28

1

IDPH does not have resources to speciate soil samples; the DePue Group is welcome to do so and to submit the information to EPA and IDPH.

29

2

5

Additional discussion included regarding common cadmium exposures.

30

5

1

ATSDR criteria for selecting the site conclusion category were followed. IDPH will add a second conclusion statement that no immediate concern exists, as demonstrated by the biological screening data.

30

5

12

The blood and urine screening was not a comprehensive study of the exposed population. The limited number of people tested, and the tests performed, were designed only to answer the question of whether immediate intervention was needed to stop exposure. The conclusion category is correct.

31

3

6

Sentence modified

31

4

2

Sentence modified.

61

Table 16

Table 16 removed. General discussion of air sampling conducted in 1990s included in text.

This DePue/New Jersey Zinc/Mobil Chemical Corporation Site public health assessment wasprepared by the Illinois Department of Public Health under a cooperative agreement with the Agencyfor Toxic Substances and Disease Registry. It is in accordance with approved methodology andprocedures existing at the time the public health assessment was begun.

Gail D. GodfreyTechnical Project OfficerSPS, SSAB, DHAC, ATSDR

The Division of Health Assessment and Consultation, ATSDR, has reviewed this public health assessment and concurs with its findings.